import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';

class Square extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      value: null
    }
  }
  render() {
    return (<button className="square"
      onClick={() => {
        this.props.onClick();
      }}>
      {this.props.value}
    </button>)
  }
}

class Board extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      squares: Array(9).fill(null),
      isXnext: true,
    }
  }
  handleClick(i) {
    const squares = this.state.squares.slice();
    squares[i] = this.state.isXnext ? 'X' : 'O';
    this.setState({
      squares: squares,
      isXnext: !this.state.isXnext,
    });
  }
  renderSquare(i) {
    return <Square value={this.state.squares[i]}
      onClick={() => {
        this.handleClick(i)
      }} />
  }
  render() {
    const winner = calculateWinner(this.state.squares);
    let status;
    if (winner) {
      status = 'Winner: ' + winner;
    } else {
      status = 'Next player: ' + (this.state.xIsNext ? 'X' : 'O');
    }
    return (
      <div>
        <div className='status'>{status}</div>
        <div className='board-row'>
          {this.renderSquare(0)}
          {this.renderSquare(1)}
          {this.renderSquare(2)}
        </div>
        <div className='board-row'>
          {this.renderSquare(3)}
          {this.renderSquare(4)}
          {this.renderSquare(5)}
        </div>
        <div className='board-row'>
          {this.renderSquare(6)}
          {this.renderSquare(7)}
          {this.renderSquare(8)}
        </div>
      </div>
    )
  }
}

class Game extends React.Component {
  render() {
    return (
      <div className='game'>
        <div className="game-board">
          <Board />
        </div>
        <div className="game-info">
          <div>{/* status*/}</div>
          <ol>{/*TODO*/}</ol>
        </div>
      </div>
    )
  }
}


ReactDOM.render(
  <Game />,
  document.getElementById('root')
)

function calculateWinner(squares) {
  const lines = [
    [0, 1, 2],
    [3, 4, 5],
    [6, 7, 8],
    [0, 3, 6],
    [1, 4, 7],
    [2, 5, 8],
    [0, 4, 8],
    [2, 4, 6],
  ];
  for (let i = 0; i < lines.length; i++) {
    const [a, b, c] = lines[i];
    if (squares[a] && squares[a] === squares[b] && squares[a] === squares[c]) {
      return squares[a];
    }
  }
  return null;
}

